These days I'm biggest on open world games, so my favourite native games are likely OpenMW (Morrowind), Mad Max and Shadow of Mordor.
I do enjoy my isometric RPGs as well, so Wasteland 2 and a few other modern titles are great and classics like the Baldur's Gate games, Icewind Dale and Planescape Torment are also up there.

There's also some pretty great open source stuff I enjoy, some of which have been around long enough I assume some of you would recognise the names, others that are newer. Battle for Wesnoth, 0 A.D. and Alex the Allegator 4 have all consumed decent chunks of my time.

I was lucky enough to get Rocket League for free from Nvidia when I bought my EVGA GTX 1050 Ti SSC. Unfortunately my desktop died a week later so I haven't played it since then (probably over a year now...). I didn't get the chance to try it out on Linux, just Windows 10, but I thought it was really fun.